1. Field of the Invention
The present invention relates to a driving control device for a vehicle device to control the traveling of the vehicle device by tilting a single operation lever of an operation lever device forward, backward, right or left.
2. Description of the Related Art
For example, a driving control device for a vehicle device, which controls traveling of a vehicle device such as a bulldozer by tilting a single operation lever, is already know.
FIG. 16 shows an example of a driving control device for a conventional bulldozer (vehicle device). FIGS. 17(a) and 17(b) show appearance of the operation lever device configuring the above driving control device, and FIG. 18 shows an inside structure of the operation lever device.
It is seen from FIG. 18 that operation lever device 205 has device body 207 and operation lever 206 which is mounted to be tiltable on the device body 207 through universal joint 250.
The universal joint 250 is provided with piece member 213 which has support shaft 209 and support shaft 210 mutually intersecting at right angles as shown in FIG. 19. The piece member 213 is connected to forked bracket 212 fixed to mounting plate 211 through the support shaft 210. The operation lever 206 is connected to the piece member 213 through the support shaft 209.
The operation lever 206 can be tilted in two directions so to mutually intersect at right angles with the device body 207 through the universal joint 250 as described above.
The device body 207 has four pistons 201, 202, 203, 204, a housing for accommodating the pistons 201 to 204 and mounting plate 211.
The device body 207 has top ends of the four pistons 201, 202, 203, 204 protruded, from the top mounting plate 211. The four pistons 201 to 204 are disposed to form a square when viewed from above as shown in FIG. 17(a).
Disk plate 208 having a substantially disk form is connected to the operation lever 206. The disk plate 208 has its undersurface contacted with the top ends of the respective pistons 201, 202, 203, 204 when the operation lever 206 is neutral.
The term neutral is used to mean a state that pressure reducing valves 218 to 221 do not output a signal in FIG. 16. Generally, it is configured that the operation lever 206 is parallel to the respective pistons 201, 202, 203, 204 and perpendicular to the mounting plate 211 as shown in FIG. 18.
Accordingly, when the operation lever is tilted, the respective pistons 201, 202, 203, 204 are moved according to a tilted direction and amount of the operation lever 206.
As shown in FIG. 16, the operation lever device 205 is supplied with a pilot pressure oil from fixed displacement hydraulic pump 222. Relief valve 222V and tank 223 are connected to the operation lever device 205.
The pistons 201, 202, 203, 204 are respectively provided with the pressure reducing valves 218, 219, 220, 221 via an unshown set spring. Output ports of the pressure reducing valves 218, 219, 220, 221 are connected to the pilot pipe passages 214, 215, 216, 217 respectively.
Next, the operation will be described with reference to FIG. 18. When the operation lever 206 which is in the neutral position is tilted about the support shaft 209 to the left in the drawing (in a direction of forward F), the piston 204 is pushed down in a direction of arrow A by the disk plate 208.
Then, stroke S (displacement) of the piston 204 has a magnitude corresponding to a tilted amount of the operation lever 206.
When the piston 204 is pushed down, the pressure reducing valve 218 increases its opening area through the set spring. The pressure reducing valve 218 outputs a pilot pressure corresponding to the opening area to the pilot pipe passage 214.
The opening area of the pressure reducing valve 218 is determined depending on a balance between the output pilot pressure and the spring tension. The spring tension in the balance position corresponds to stroke S. Therefore, pilot pressure Pp output from the pilot pipe passage 214 has the magnitude corresponding to the tilted amount of the operation lever 206.
FIG. 20 shows a relation between the stroke S and the pilot pressure Pp. When the operation lever 206 is operated to move the piston 204 from stroke position S0 corresponding to the neutral position shown in FIG. 18 to position SF to output maximum output Ppmax, the pilot pressure Pp output from the pilot pipe passage 214 is variable from drain pressure Pp0 of the tank 223 to set pressure Ppmax of the relief valve 222V.
It is designed that when the piston 204 reaches position SF to output the maximum output Ppmax, the operation lever 206 stops its stroke and its further movement is restricted.
The zone between the stroke position S0 and position Si is a dead zone, in which the pilot pressure Pp output from the pilot pipe passage 214 remains to be drain pressure Pp0 and does not change even if the operation lever 206 is tilted.
It was described above that the piston 204 is moved according to the tilting of the operation lever 206, and the oil pressure signal indicating the pilot pressure Pp is output from the pilot pipe passage 214. The oil pressure signal indicating the pilot pressure Pp is also output from the pilot pipe passages 215, 216, 217 in the same way when the pistons 201, 202, 203 are moved according to the titling of the operation lever 206.
The bulldozer having the driving control device of FIG. 16 is provided with left crawler 236 and right crawler 238 on the left and right sides of its body. The left crawler 236 is driven by left traveling hydraulic motor 235. The right crawler 238 is driven by right traveling hydraulic motor 237.
The left traveling hydraulic motor 235 is an actuator for operating the left crawler 236 in two directions, namely forward and backward. The right traveling hydraulic motor 237 is an actuator for operating the right crawler 238 in two directions, namely forward and backward.
The operation lever device 205 is connected to swash plate control cylinders 230, 231 for left and right variable displacement hydraulic pumps 233, 234 through drive signal generation circuit 229. The left and right for variable displacement hydraulic pumps 233, 234 are connected to the left and right hydraulic motors 235, 237 respectively.
The drive signal generation circuit 229 comprises shuttle valves 225, 226, 227, 228 for comparing oil pressure signals output from the two neighboring pistons (203 and 204, 204 and 201, 201 and 202 or 202 and 203) to output a signal of a larger pressure.
The pilot pipe passage 214 is connected to port F which is an inlet port for either of the shuttle valves 225, 226. Similarly, the pilot pipe passage 215 is connected to port B. The pilot pipe passage 216 is connected to port R. The pilot pipe passage 217 is connected to inlet port L.
Outlet port of the shuttle valve 225 is connected to cylinder chamber 230F of the swash plate control cylinder 230. Outlet port of the shuttle valve 226 is connected to cylinder chamber 231F of the swash plate control cylinder 231. Outlet port of the shuttle valve 227 is connected to cylinder chamber 231B of the swash plate control cylinder 231. Outlet port of the shuttle valve 228 is connected to cylinder chamber 230B of the swash plate control cylinder 230.
Pressure oil supplied to the cylinder chamber 230F tilts the swap plate of the variable displacement hydraulic pump 233 to make a forward rotation of the left traveling hydraulic motor 235 so to move forward the left crawler 236. The pressure oil supplied to the cylinder chamber 230B tilts the variable displacement hydraulic pump 233 to make backward rotation of the left traveling hydraulic motor 235 so to move backward the left crawler 236.
Similarly, the pressure oil supplied to the cylinder chamber 231F tilts the swash plate of the variable displacement hydraulic pump 234 to make a forward rotation of the right traveling hydraulic motor 237 so to move forward the right crawler 238. The pressure oil supplied to the cylinder chamber 231B tilts the swash plate of the variable displacement hydraulic pump, 234 to make backward rotation of the right traveling hydraulic motor 237 so to move backward the right crawler 238.
The variable displacement hydraulic pump 233, the variable displacement hydraulic pump 234 and the fixed displacement hydraulic pump 222 are driven by engine 232.
Thus, the left and right traveling hydraulic motors 235, 237 are driven according to the pressure of the oil pressure signal Pp generated by the operation lever device 205.
Therefore, the left and right traveling hydraulic motors 235, 237 can be driven in the direction of rotation according to the tilted direction of the operation lever 206 and driven at a speed according to the tilted amount of the operation lever 206 so to operate the left and right crawlers 236, 238 respectively.
Next, the movements of a vehicle will be described. FIG. 21 shows the movements of the vehicle (bulldozer) in correspondence with the tilted directions of the operation lever 206.
Tilting of the operation lever 206 from the neutral position in forward (straight) direction F will be described.
At this time, only the piston 204 of the operation lever device 205 is moved. Therefore, the oil pressure signal Pp is output from the pilot pipe passage 214 only. The oil pressure signal Pp is entered the drive signal generation circuit 229 and input to the shuttle valves 225, 226.
At this time, because the pilot pressure is not applied to the inlet ports L, R, the oil pressure signal Pp is output from the shuttle valves 225, 226.
A drive signal (pilot pressure) corresponding to the forward movement direction of the left traveling hydraulic motor 235 is output from the shuttle valve 225. The output pilot pressure oil is supplied to the cylinder chamber 230F corresponding to the left traveling forward movement of the swash plate control cylinder 230.
Similarly, a drive signal (pilot pressure) corresponding to the forward movement direction of the right traveling hydraulic motor 237 is output from the shuttle valve 226. The output pilot pressure oil is supplied to the cylinder chamber 231F corresponding to the right traveling forward movement of the swash plate control cylinder 231.
Thus, the swash plate of the left traveling hydraulic pump 233 is changed to a tilted angle corresponding to the forward movement. The left traveling hydraulic pump 233 ejects the pressure oil according to the tilted angle. The pressure oil ejected from the left traveling hydraulic pump 233 is supplied to a supply port corresponding to the forward movement of the left traveling hydraulic motor 235.
Similarly, the swash plate of the right traveling hydraulic pump 234 is changed to a tilted angle corresponding to the forward movement. The right traveling hydraulic pump 234 ejects the pressure oil according to the tilted angle. The pressure oil ejected from the right traveling hydraulic pump 234 is supplied to a supply port corresponding to the forward movement of the right traveling hydraulic motor 237.
Here, pressures output from the shuttle valves 225, 226 are the same. Therefore, the tilted angles are also the same. Amounts of flow of the pressure oils supplied to the left and right traveling hydraulic motors 235, 237 are the same because the amounts of flow of the pressure oils ejected from the left and right traveling hydraulic pumps 233, 234 become the same.
Therefore, the left and right traveling hydraulic motors 235, 237 are rotated at the same speed. As a result, the left and right crawlers 236, 238 are driven in the forward direction at the same speed, so that the vehicle (bulldozer) moves forward (straight) as indicated by arrow F in FIG. 21. The vehicle speed corresponds to the tilted amount of the operation lever 206.
Similarly, when the operation lever 206 is tilted in any direction, a drive signal corresponding to the tilted direction of the lever is output from the respective shuttle valves 225 to 228 of the drive signal generation circuit 229.
When the operation lever 206 is tilted in backward (straight) direction B, only the piston 202 of the operation lever device 205 is moved. Therefore, the oil pressure signal Pp is output from only the pilot pipe passage 215. The oil pressure signal Pp is entered the drive signal generation circuit 229 and input to the shuttle valves 227, 228.
At this time, the oil pressure signal Pp is output from the shuttle valves 227, 228 because the pilot pressure does not act on the inlet ports L, R.
A drive signal (pilot pressure) corresponding to the backward direction of the right traveling hydraulic motor 237 is output from the shuttle valve 227. The output pilot pressure oil is supplied to the cylinder chamber 231B corresponding to right traveling backward movement of the swash plate control cylinder 231.
Similarly, a drive signal (pilot pressure) corresponding to the backward movement direction of the left traveling hydraulic motor 235 is output-from the shuttle valve 228. The output pilot pressure oil is supplied to the cylinder chamber 230B corresponding to the left traveling backward movement of the swash plate control cylinder 230.
Thus, the swash plate of the right traveling hydraulic pump 234 is changed to a tilted angle corresponding to the backward movement. The right traveling hydraulic pump 234 ejects the pressure oil corresponding to the tilted angle. The pressure oil ejected from the right traveling hydraulic pump 234 is supplied to a supply port corresponding to the backward movement side of the right traveling hydraulic motor 237.
Similarly, the swash plate of the left traveling hydraulic pump 233 is changed to a tilted angle corresponding to the backward movement. The left traveling hydraulic pump 233 ejects a pressure oil corresponding to the tilted angle. The pressure oil ejected from the left traveling hydraulic pump 233 is supplied to a supply port corresponding to the backward movement side of the left traveling hydraulic motor 235.
Here, pressures output from the shuttle valves 227, 228 are the same. Therefore, the tilted angles are also the same. Amounts of flow ejected by the left and right traveling hydraulic pumps 233, 234 are the same, so that the amounts of flow supplied to the left and right traveling hydraulic motors 235, 237 are the same.
Therefore, the left and right traveling hydraulic motors 235, 237 rotate at the same speed. As a result, the left and right crawlers 236, 238 are driven in the backward direction at the same speed, and the vehicle (bulldozer) moves backward (straight) as indicated by arrow B in FIG. 21.
When the operation lever 206 is tilted in right direction R, only the piston 201 of the operation lever device 205 is moved. Therefore, the oil pressure signal Pp is output from the pilot pipe passage 216 only. The oil pressure signal Pp is entered the drive signal generation circuit 229 and input to the shuttle valves 226, 227.
At this time, the pilot pressure does not act on the inlet ports F, B, so that the oil pressure signal Pp is output from the shuttle valves 226, 227.
The pilot pressure oil output from the shuttle valve 226 is supplied to the cylinder chamber 231F of the swash plate control cylinder 231. The pilot pressure oil output from the shuttle valve 227 is supplied to the cylinder chamber 231B of the swash plate control cylinder 231. Therefore, the swash plate control cylinder 231 does not operate.
And, the pilot pressure does not act on the cylinder chambers 230F, 230B of the swash plate control cylinder 230, so that the swash plate control cylinder 230 does not operate either.
Therefore, both the left and right crawlers 236, 238 do not operate, and the vehicle (bulldozer) stops.
When the operation lever 206 is tilted in left direction L, only the piston 203 of the operation lever device 205 is moved. Therefore, the oil pressure signal Pp is output from the pilot pipe passage 217 only. This oil pressure signal Pp is entered the drive signal generation circuit 229 and input to the shuttle valves 225, 228.
At this time, the pilot pressure does not act on the inlet ports F, B, so that the oil pressure signal Pp is output from the shuttle valves 225, 228.
The pilot pressure oil output from the shuttle valve 225 is supplied to the cylinder chamber 231F of the swash plate control cylinder 230. The pilot pressure oil output from the shuttle valve 228 is supplied to the cylinder chamber 230B of the swash plate control cylinder 230. Therefore, the swash plate control cylinder 230 does not operate.
And, the pilot pressure does not act on the cylinder chambers 231F, 231B of the swash plate control cylinder 231, so that the swash plate control cylinder 231 does not operate either.
Therefore, both the left and right crawlers 236, 238 do not operate, and the vehicle (bulldozer) stops.
Thus, when the operation lever 206 is tilted in forward direction F, the vehicle moves forward (straight). When the operation lever 206 is tilted in backward direction B, the vehicle moves backward (straight). When the operation lever 206 is tilted in right direction R, the vehicle stops moving. When the operation lever 206 is tilted in left direction L, the vehicle stops moving.
When the operation lever 206 is tilted in a direction to the midpoint between the directions F and R, the vehicle makes a forward right turn. When the operation lever 206 is tilted in a direction to the midpoint between the directions R and B, the vehicle makes a backward left turn. When the operation lever 206 is tilted in a direction to the midpoint between the directions B and L, the vehicle makes a backward right turn. And, when thee operation lever 206 is tilted in a direction to the midpoint between the directions L and F, the vehicle makes a forward left turn.
The driving control device for the vehicle device described above could not turn the vehicle on the spot, so-called spin tun, by operating the left crawler 236 and the right crawler 238 at the same speed but in opposite directions from each other.
As a driving control device enabling the spin turn of a vehicle, there is a driving control device shown in FIG. 22 used for a vehicle such as a skid steering loader.
In FIG. 22, like reference numerals designate like or corresponding elements of FIG. 16, and their detailed descriptions are omitted.
The vehicle such as a skid steering loader has an operation pattern by the operation lever 206 different from that of the vehicle such as a bulldozer. Therefore, the connection of the oil pressure pipe passages between the drive signal generation circuit 229 and the swash plate control cylinders 230, 231 is partly different from that of the driving control device shown in FIG. 16.
Specifically, in the driving control device shown in FIG. 22, the outlet port of the shuttle valve 225 in the drive signal generation circuit 229 is connected to the cylinder chamber 231F of the swash plate control cylinder 231. The outlet port of the shuttle valve 226 is connected to the cylinder chamber 230F of the swash plate control cylinder 230.
Movements of the vehicle (skid steering loader) having the driving control device described above will be described in correspondence with tilted directions of the operation lever 206 with reference to FIG. 23.
When the operation lever 206 is tilted in forward movement direction F, the vehicle moves forward (straight ahead) and when it is tilted in backward direction B, the vehicle moves backward (straight).
When the operation lever 206 is tilted in right spin turn direction R, only the piston 201 of the operation lever device 205 is moved. Therefore, the oil pressure signal Pp is output a from the pilot pipe passage 216 only. This oil pressure signal Pp is entered the drive signal generation circuit 229 and input to the shuttle valves 226, 227.
At this time, the pilot pressure does not,act on the inlet ports F, B, so that the oil pressure signal Pp is output from the shuttle valves 226, 227.
A drive signal (pilot pressure) corresponding to the forward direction of the left traveling hydraulic motor 235 is output from the shuttle valve 226. The output pilot pressure oil is supplied to the cylinder chamber 230F corresponding to the left traveling forward movement of the swash plate control cylinder 230.
Similarly, a drive signal (pilot pressure) corresponding to the backward direction of the right traveling hydraulic motor 237 is output from the shuttle valve 227. The output pilot pressure oil is supplied to the cylinder chamber 231B corresponding to the right traveling backward movement of the swash plate control cylinder 231.
Thus, the swash plate of the left traveling hydraulic pump 233 is switched to a tilted angle corresponding to the forward movement. The left traveling hydraulic pump 233 ejects the pressure oil according to the tilted angle. The pressure oil ejected from the left traveling hydraulic pump 233 is supplied to a supply port corresponding to the forward movement side of the left traveling hydraulic motor 235.
Similarly, the swash plate of the right traveling hydraulic pump 234 is switched to a tilted angle corresponding to the backward movement. The right traveling hydraulic pump 234 ejects a pressure oil according to the tilted angle. The pressure oil ejected from the right traveling hydraulic pump 234 is supplied to a supply port corresponding to the backward movement side of the right traveling hydraulic motor 237.
Here, the pressures output from the shuttle valves 226, 227 are the same. Accordingly, the tilted angles are also the same. Amounts of flow supplied to the left and right traveling hydraulic motors 235, 237 are the same because the amounts of flow ejected by the left and right hydraulic pumps 233, 234 become the same.
Therefore, the left and right traveling hydraulic motors 235, 237 rotate at the same speed but in opposite directions. As a result, the left crawler 236 moves in the forward direction while the right crawler 238 moves in the backward direction, so that the vehicle (bulldozer) makes a right spin turn.
When the operation lever 206 is tilted in left spin turn direction L, only the piston 203 of the operation lever devil 205 is moved. Accordingly, the oil pressure signal Pp is output from the pilot pipe passage 217 only. This oil pressure signal Pp is entered the drive signal generation circuit 229 and input to the shuttle valves 225, 228.
At this time, the pilot pressure does not act on the inlet ports F, B. so that the oil pressure signal Pp is output from the shuttle valves 225, 228.
A drive signal (pilot pressure) corresponding to the forward movement direction of the right traveling hydraulic motor 237 is output from the shuttle valve 225. The output pilot pressure oil is supplied to the cylinder chamber 231F corresponding to the right traveling forward movement of the swash plate control cylinder 231.
Similarly, a drive signal (pilot pressure) corresponding to the backward direction of the left traveling hydraulic motor 235 is output from the shuttle valve 228. The output pilot pressure oil is supplied to the cylinder chamber 230B corresponding to the left traveling backward movement of the swash plate control cylinder 230.
Thus, the swash plate of the right traveling hydraulic pump 234 is changed to a tilted angle corresponding to the forward movement. The right traveling hydraulic pump 234 ejects the pressure oil according the tilted angle. The pressure oil ejected from the right traveling hydraulic pump 234 is supplied to a supply port corresponding to the forward movement side of the right traveling hydraulic motor 237.
Similarly, the swash plate of the left traveling hydraulic pump 233 is switched to a tilted angle corresponding to the backward movement. The left traveling hydraulic pump 233 ejects the pressure oil according to the tilted angle. The pressure oil ejected from the left traveling hydraulic pump 233 is supplied to a supply port corresponding to the backward movement side of the left traveling hydraulic motor 235.
Here, the pressures output from the shuttle valves 225, 228 are the same. Accordingly, the tilted angles are also the same. Amounts of flow supplied to the left and right traveling hydraulic motors 235, 237 become the same because the a mounts of flow ejected from the left and right traveling hydraulic pumps 233, 234 become the same.
Therefore, the left and right traveling hydraulic motors 235, 237 rotate at the same speed but in opposite directions. As a result, the right crawler 238 moves in the forward direction while the left crawler 236 moves in the backward direction, so that the vehicle (bulldozer) makes a left spin turn.
And, when the operation lever 206 is tilted in a direction to the midpoint between the directions F and R, the vehicle makes a forward right turn. And, when the operation lever 206 is tilted in a direction to the midpoint between the directions R and B, the vehicle makes a backward right turn.
When the operation ever 206 is tilted in a direction to the midpoint between the directions B and L, the vehicle makes a backward left turn. And, when the operation lever 206 is tilted in a direction to the midpoint between the directions L and F, the vehicle makes a forward left turn.
By the driving control device described above, the vehicle can make a spin turn by operating the operation lever 206.
However, the driving control device shown in FIGS. 22, 23 has an operation pattern (hereinafter called the skid pattern) that when the vehicle is moved backward, a relation between the tilting direction of the operation lever 206 and the traveling direction (turning direction) of the vehicle is reversed.
The skid patterns 5 own in FIGS. 22 and 3 are different from the operation patterns (hereinafter called the bull-pattern) of the driving control device of the bulldozer shown in FIGS. 17 and 21. Therefore, an operator skilled in the operation of the bulldozer has a different operation feeling about the skid pattern.
It is an object of the present invention to provide a driving control device for a vehicle device, which can make a spin turn of a vehicle without changing the bull-pattern.
To achieve the above object, the invention described in claim 1 is a driving control device for a vehicle device which has an operation lever device (1) for outputting a signal to instruct a traveling speed and a traveling direction of a vehicle by tilting a single operation lever (40) forward, backward, left and right, and hydraulic motor control means (6, 8) for controlling rotation speeds and rotation directions of two hydraulic motors (3L, 3R) for driving respective traveling devices (2L, 2R) on left and right sides of the vehicle body according to the signal from the operation lever device (1), and which controls the traveling of the vehicle device by operating the operation lever (40) of the operation lever device (1), wherein the driving control device comprises:
spin turn instruction means (140) which outputs a signal to make the two hydraulic motors (3L, 3R) have the same rotation speed but in different rotation directions from each other by rotating the opera ion lever (40) of the operation lever device (1).
According to the invention described in claim 1, the spin turn of the vehicle can be made by turning the operation lever by following the bull-pattern of the operation lever device.
The invention described in claim 2 is the invention of claim 1, wherein the spin turn instruction means (140) outputs the signal only when the operation lever (40) of the operation lever device (1) is in a neutral position with respect to tilting directions.
According to the invention described in claim 2, the spin turn of the vehicle can be made only when the operation lever is in the neutral position.
The invention described in claim 3 is the invention of claim 1, wherein the spin turn instruction means (140) is provided with a changeover switch (180) to output the signal according to a state of the changeover switch (180) and a tilting operation of the operation lever (40) of the operation lever device (1).
According to the invention described in claim 3, the vehicle can make a spin turn on the basis of the state of the changeover switch and the tilting operation of the operation lever upon following the bull-pattern of the operation lever device.
The invention described in claim 4 is the invention described in any of claims 1 to 3, wherein the spin turn instruction means (140, 190) provides a dead band in a predetermined tilting range from the neutral position of the operation lever (40) of the operation lever device (1).
According to the invention described in claim 4, when the spin turn is instructed by the operation lever device, the operation lever is operated with play because the dead band was disposed in a predetermine tilting range from the neutral position of the operation lever, and a signal is not output when the operation lever is tilted just a little. Therefore, good operability can be obtained without requiring a delicate operation of the operation lever.